One type of heretofore available copying system synthesizes a color copy of an image by exposing three times in raster-scan fashion the entire surface of a light-sensitive paper to ultraviolet light rays carrying the image. In such a system, three color selective filters receive the image-carrying light rays and separate them into three wavelength components corresponding to the colors red, green, and blue. The light-sensitive paper is typically exposed to only one of the three wavelength components during a given exposure pass.
A copying system of this type suffers from the disadvantage of requiring three complete raster-scan passes over the surface of the light-sensitive paper to form the color copy, thereby consuming a relatively large amount of time to complete the copying process. Moreover, such a copying system relies upon the mechanical accuracy of the raster-scanning apparatus to provide on the light-sensitive paper convergence of the light rays corresponding to the three color components of an image pixel.